Trace Elements In Liquids Research Articles

A hybrid method combining discharge-assisted laser induced breakdown spectroscopy with wavelet transform for trace elemental analysis in liquid targets

A hybrid method combining discharge-assisted laser-induced breakdown spectroscopy (D-LIBS) with wavelet transform represents a highly promising detection technology for the quantitative determination of trace elements in liquids.

Characteristics of indirect laser-induced plasma from a thin film of oil on a metallic substrate

Optical emissions from the major and trace elements embodied in a transparent gel prepared from cooking oil were detected after the gel was spread in a thin film on a metallic substrate. Such emissions are due to the indirect breakdown of the coating layer. The generated plasma, a mixture of substances from the substrate, the layer, and the ambient gas, was characterized using emission spectroscopy. The characteristics of the plasma formed on the metal with and without the coating layer were investigated. The results showed that Al emission induced from the aluminum substrates coated with oil films extends away from the target surface to ablate the oil film. This finally formed a bifurcating circulation of aluminum vapor against a spherical confinement wall in the front of the plume, which differed from the evolution of the plasma induced from the uncoated aluminum target. The strongest emissions of elements from the oil films can be observed at 2 mm above the target after a detection delay of 1.0 μs. A high temperature zone has been observed in the plasma after the delay of 1.0 μs for the plasma induced from the coated metal. This higher temperature determined in the plasma allows the consideration of the sensitive detection of trace elements in liquids, gels, biological samples, or thin films.

Indirect laser-induced breakdown of transparent thin gel layer for sensitive trace element detection

Optical emissions from major and trace elements embodied in a transparent gel prepared from cooking oil were detected when the gel was spread in thin film on a metallic substrate and a plasma was induced on the substrate surface using nanosecond infrared pulsed laser. Such emissions are due to indirect breakdown of the coating layer. The generated plasma, a mixture of substances from the substrate, the layer, and the ambient gas, was characterized using emission spectroscopy. Temperature higher than 15 000 K determined in the plasma allows considering sensitive detection of trace elements in liquids, gels, biological samples, or thin films.

Detection of trace elements in liquids by laser-induced breakdown spectroscopy with a Meinhard nebulizer.

The laser-induced breakdown spectroscopy of magnesium, manganese, and chromium atoms by use of a commercial Meinhard nebulizer originally designed for inductively coupled plasma measurements is described. This is the first time, to our knowledge, that this nebulizer has been used for laser-induced breakdown spectroscopy measurements. The limit of detection is slightly lower when the nebulizer rather than a liquid jet is used in single-pulse laser excitation. In addition we present the response characteristics of the nebulizer, such as effects of variations in purge gas and liquid flow rate, that are different from normal operating specifications. The effects of gate delay, gate width, and laser power variations were also studied. The objective of the present research has been to consider a new operating mode and conditions in which a better limit of detection of trace elements in water can be obtained.

An external-beam charged-particle (alpha) activation system for direct trace element analysis in liquids

An external-beam system based on charged-particle activation analysis for determination of trace elements in liquids has been developed at the Variable Energy Cyclotron Centre, Calcutta. The system developed is direct, instrumental, non-destructive, simple and suitable for both aqueous and non-aqueous samples. The authors gives the construction details of the system and its standardization for quantitative estimation of transition metals. Medium-energy alpha particles were used. As part of the standardization process the beam energy, beam current, observed interferences, minimum detection limits, system linearity, reproducibility and precision are discussed. The authors have used mainly aqueous and crude oil samples during this work. A novel method for calibrating the target position with respect to the beam is reported.